Material properties of silicone

[Natly]

Hi everyone,
I am going to perform comparison the experimental data with simulation using Workbench simulation. The experiment was performed with silicone tube and flowing water inside, which corresponds the blood vessel. I consider silicone as a linear elastic uncompressible material. But if I put the maximum value of pressure (75000 Pa) on the internal wall of the pipe - then I see in Ansys Simulation that the wall is ruptured. Silicone can not stand the real pressure from experiment.
Is enyone has any idea why is it happened? I assume that the possible reason for it could be wrong material properties formulation (I mean as a linear elastic uncompressible material). May be I should apply other material properties of the silicone?
Also I saw that sometimes for modelling material properties apply the experimental data( curve fitting data strain vs stress),but in my case I applied just one value for Young's Modulus, Poisson's ratio and Density. Could you explaine for me please, where is the difference? I an beginning user of Ansys Sortware, sorry if my questions seem very strange!:confused:
Thanks anyway!

[Jorgen]

First, if I recall right, a linear elastic incompressible cylinder with internal pressure becomes unstable at a certain pressure level. That might be what is going on in your case. Or perhaps your material representation and parameters might not be quite right.

I would recommend that you use a neo-Hookean material model with some compressibility.

-Jorgen